Surface variables assimilated / read in EKF_MAIN

From cycle 37 EKF is implemented in research/development mode. The following tiles and variables are modified:

NATURE

WG2/WG1/TG2/TG1

The uppermost two levels in ISBA of soil moisture and temperature are assimilated. With CANARI/CANARI_OI_MAIN by an OI method, by CANARI_SURFEX_EKF by an Extended Kalman Filter (EKF).

For 2012 it is planned to have a re-writing of OI_MAIN/EKF_MAIN to be the same binary in order to be able to apply the work done for OI_MAIN in EKF_MAIN and thus reduce the maintainance costs.